What does working in an iron lung mean?

An iron lung is a negative pressure ventilator that was widely used in the early 20th century to treat respiratory failure. It consists of a sealed metal chamber that encloses the patient's body up to the neck, with the head protruding from the end. The chamber is then sealed, and the pressure inside is lowered. This creates negative pressure, causing the patient's lungs to expand and fill with air. The cycle of negative and positive pressure is repeated, allowing the patient to breathe. I can't find any information about working in an iron lung. People who worked in iron lungs were essentially paralyzed, and needed constant medical care.